Last year, a large flood was forecasted for Grand Forks, BC, one that would rival the record-breaking disaster that devastated the community in 2018.
City staff were quick to act, readying their emergency response plan and putting up temporary protection works. Luckily, the flood never came. But the non-event did reveal the far-reaching impacts of the City’s Floodplain Naturalization Project and completed dikes.
Mayor Everett Baker immediately noted the difference in emergency response: “Staff were preparing the evacuation maps and told us that 500 people less were in evacuation zones, and almost two kilometers less of temporary flood protection would have been needed. The project isn’t even completed, and we are already seeing what a difference it makes — it was business as usual downtown during the flood.”
The new dikes and neighbourhood buyout meant that emergency planning became much simpler. “The emergency management staff and public works crews could focus on areas that we couldn’t even consider in previous floods,” said Graham Watt, Manager of Strategic Initiatives and Flood Recovery at Grand Forks.
The neighbourhood in question was North Ruckle, which borders the increasingly flood-prone Kettle River. In 2018, North Ruckle was hard-hit by a 200-year flood event; floodwaters overtopped then breached the old dike, and even reached the eaves of some houses.
“We did not want to go through that kind of impactful disaster again,” said Mayor Baker on the decision to not rebuild the neighbourhood. Instead, the City began the process to re-naturalize the area as part of the broader flood mitigation program, creating several hectares of floodplain that would give the river’s water somewhere to go. Thankfully, a natural asset management project was already underway in Grand Forks that could inform the neighbourhood’s transformation.
THEN: Assessing natural assets in Kettle River
Back in 2016, Grand Forks joined a pilot project with NAI and the David Suzuki Foundation. While the initial intention was to assess the role of their oxbow wetlands in stormwater management, 2017’s moderate flood made them change course.
“A trend we noticed is that people would be building big houses next to the river, raising land around their houses, building private dikes, and we wanted to know: what if everybody did this?” explained Watt. “What if we lost the ecological value of floodplains, and how do we know how valuable these floodplains are?”
The final project resulting from these questions focused on flood mitigation benefits from the Kettle River floodplain under different development scenarios. The results demonstrated that an intact floodplain provides—at a minimum—between $500 and $3,500/hectare in flood damage reduction for downtown buildings during high flow events.
Using the results provided by NAI and engineering assessments following the 2018 flood, the City was successful in their application for disaster mitigation funding leading to the current naturalization initiative, which aligns with policy and recovery actions that make up Grand Forks’ flood mitigation program. [See NAI’s earlier update].
NOW: Floodplain Naturalization Project
The floodplain naturalization project resulting from the analysis and funding from the federal Disaster Mitigation and Adaptation Fund includes two key features:
- Establish a system of dikes: one to protect Grand Forks’ downtown and remove stormwater; a second to safeguard an area housing critical infrastructure, including an electrical switchyard, two industrial plants, and a wastewater treatment plant; and a third to protect a neighbourhood and industrial area upstream.
- Naturalize and restore floodplains in North Ruckle and riparian zones to support natural asset improvement and green infrastructure protection, including rural areas upstream of the community.
Removing the North Ruckle neighbourhood would provide a ‘pressure release valve’ for Kettle River. Watt explained their rationale for managed retreat:
“Council considered rebuilding the 1974 dike that was next to the river before committing to remove the dike and naturalize several hectares of floodplain outside of the new setback dike,” Watt explained. “To reduce impacts on the river and downstream areas, the City ultimately needed to provide a place for the river to go during the flood. If you build dikes on both sides of the river, then you can back the water up, increasing velocity and causing more damage downstream — and this would not be permitted by regulators. You also need more riprap and create more habitat impacts.”
Graham Watt, Manager of Strategic Initiatives and Flood Recovery at Grand Forks
In other words, the new floodplain not only enhances the ecosystem and gives the river somewhere to go, but it also helps the engineered assets work better — all of which reduces impacts on the community and the ecosystem.
The City worked with their engineers and planning consultants to develop a design brief for a multi-stakeholder design charrette for the floodplain naturalization. The resulting preferred concept detailed a floodable natural area on the west side allowing for interactive human use and interpretive space, and a natural area on the east side dedicated to riparian restoration. The east side has a 2 hectare off-channel river habitat plus 2 hectares of riparian area — now constructed and planted — which also satisfies fish habitat offsetting requirements.
Navigating the North Ruckle Buyout
Following extensive dialogue with property owners, Grand Forks worked towards a buyout program during 2019 and early 2020, while hydrological analysis and dike system design was underway.
Evaluating equity post-flood poses many challenges, with multiple constraints to find an acceptable outcome for both residents and the City. Council aimed to have as many voluntary agreements as possible, and in the end they accomplished their goal with 97% of property owners agreeing to a voluntary buyout.
“The buyout achieved its objectives for the City and enabled the construction of dikes and floodplain naturalization,” said Watt. “But Council needed to invest much more City resources than funders could provide to get to acceptable purchase agreements. Future funding programs could achieve greater success for homeowners by having a funding level that recognizes the value of homes prior to flood damage, or the ability to buy something similar in the housing market.”
New OCP a Strong Screening Tool for Resilient Development
“Having seen a variety of planning efforts, some of the more effective ones had some kind of major trigger like drought or flooding that provided a reason to do more integrated planning for resilience,” said Watt.
A lot has changed in Grand Forks over the last six years. Triggered by a major flood and armed with results from their pilot with NAI, the City team built out their 2022 Official Community Plan (OCP) to direct further growth without creating further impacts to natural systems.
The environment is established as a foundational priority in Grand Forks’ land use strategy, with an extensive area of natural assets and floodplains identified in the OCP. The first layer of every development review in the City now evaluates environmental conditions, natural hazards, and other development constraints.
The Environmental Development Permit policies (2.4 in the OCP) help protect those areas because developments near sensitive ecosystems have more constraints. For instance, sites that get wet every few years often contain sensitive habitat and are not good places to increase development due to groundwater and flooding issues.
Having this information in the OCP has created a first screening for the Development, Building Inspection and Bylaw Services department by helping people identify the best places to build. It’s also meant developers have avoided pursuing projects in sensitive areas rather than spend the time trying to engineer new ways to build on a wet site.
The OCP also allows for increased density outside of the floodplain, making use of the abundant buildable space within the developed footprint, such as garden suites or other accessory units.
According to Baker, the new OCP been working well. “I think that’s the main thing: direct intensification in all of those nice, walkable, connected places. And that works in rural areas like ourselves or in major cities,” said Mayor Baker. “I think there’s really exciting development opportunities away from floodplains. It’s not all about restrictions but striking a balance between development and keeping natural areas.”
